1. Field of the Invention
This invention relates to measuring devices for performing assays for the accurate determination of the presence, concentration, or activity of one or more analytes in a sample applied to test strips adapted for use with the devices. The measuring devices and test strips of the invention are particularly useful in the fields of clinical chemistry, environmental testing, and chemical process control.
2. Discussion of the Art
Electrochemical measuring devices that detect the presence, concentration, or activity of one or more analytes in a solution are well known in the art. In addition, disposable electrochemical test strips adapted for use with such devices are known in the art. For example, test strips are disclosed in U.S. Pat. No. 5,628,890; strip electrodes with screen printing are disclosed in U.S. Pat. No. 5,509,410; and additional strip electrodes with screen printing are disclosed in U.S. Pat. No. 5,682,884. In such devices, a sample is applied to the test strip, and the test strip is inserted into a port on the measuring device. Such measuring devices and test strips are commercially available for home use by diabetics for the measurement of blood glucose (e.g., the PRECISION Qxc2x7Ixc2x7D blood glucose testing system manufactured and sold by MEDISENSE, Inc., Waltham, Mass.). Other devices are commercially available, for use by home users or clinicians, for the electrochemical measurement of other blood analytes and parameters, such as lactate or urea. However, in the prior art, the measurement of multiple analytes or parameters in a sample typically requires the use of multiple measuring devices, each adapted for a different testing functionality, or a single measuring device in which the user must manually switch the device between different testing functionalities.
There is, therefore, a need in the art for products and methods by which a user may perform a multiplicity of different assays with a single measuring device having a multiplicity of testing functionalities, but without having to manually reconfigure or switch between different functionalities of the device, and without the need for a complex or expensive port or test strip design.
The invention provides a multichemistry measuring apparatus and diagnostic test strips which, in combination with the multichemistry measuring apparatus, provide a multichemistry diagnostic testing system. In one aspect, the invention relates to diagnostic test strips for chemical analysis of a sample. The diagnostic test strips are adapted for use in combination with a measuring apparatus having a test port. The apparatus is capable of performing a multiplicity of testing functionalities. In this aspect, the test strip comprises a support capable of releasably engaging the test port; at least one reaction area on the support for receiving the sample; and an indicator capable of interacting with the test port to select one of the multiplicity of testing functionalities of the measuring apparatus. In one embodiment, the indicator comprises one or more electrically conductive contacts capable of engaging at least two electrically conductive pins within the test port. In such an embodiment, the electrically conductive contacts close at least one circuit between the at least two electrically conductive pins within the test port. In preferred embodiments, the electrically conductive contacts comprise a material selected from: carbon, gold, silver, platinum, nickel, palladium, titanium, copper, or lead. In preferred embodiments, the electrically conductive contacts comprise an electrically conductive printable ink. In another embodiment, the indicator comprises one or more projections or depressions capable of mechanically engaging one or more pins within the test port. In such an embodiment, the mechanical displacement of at least one of the pins results in the opening or closing of at least one circuit. In another embodiment, the indicator comprises an optically detectable pattern capable of signaling to or being detected by an optical detector in the test port. In preferred embodiments, the optically detectable indicator comprises a pattern formed by a printable ink.
In another aspect, the present invention provides a test port for use in a measuring apparatus that is capable of performing a multiplicity of testing functionalities and is adapted for use in combination with a multiplicity of different types of diagnostic test strips. Each type of test strip corresponds to at least one of the testing functionalities of the apparatus, and at least some types of test strips have indicators of the testing functionality on them. In this aspect, the test port comprises a sensor capable of specifically interacting with the indicator(s) on the test strips, thereby selecting one of the multiplicity of testing functionalities corresponding to the type of test strip. In one embodiment, the indicators on the test strips are electrically conductive, and the sensor of the test port comprises a multiplicity of electrically conductive pins. In such an embodiment, at least two of the pins can be bridged by an indicator, thereby closing an electrical circuit. In another embodiment, the indicators on the test strips comprise projections or depressions, and the sensor of the port is a pin that may be physically displaced by or into the indicators, thereby opening or closing an electrical circuit. In another embodiment, the indicators comprise an optically detectable pattern, and the sensor of the port is an optical sensor.
In another aspect, the invention provides a measuring apparatus having a multiplicity of testing functionalities for chemical analysis. The apparatus is adapted for use in combination with a multiplicity of different types of test strips. Each of the types of test strips corresponds to at least one of the testing functionalities, and at least some of the types of test strips have indicators of the testing functionality on them. The apparatus includes: a test port including a sensor capable of interacting with the indicators on the test strips to select one of the multiplicity of testing functionalities; and a multiplicity of test circuitries for specifically measuring reactions on the test strips, the reactions corresponding to the multiplicity of testing functionalities.
In some embodiments, the assay may detect the presence, concentration, or activity of one or more of the following in a sample: L-amino acids, alcohols, aldehydes, ketones, urea, creatinine, xanthines, sarcosine, glucolate, pyruvate, lactate, fructosamine, methylamine, carbon monoxide, cholesterol, hemoglobin, glycated hemoglobin, microalbumin, high density lipoproteins, low density lipoproteins, and glucose.
In some embodiments, the reaction area includes one or more reagents adsorbed to the support. The reagents are capable of reacting with an analyte in the sample. In preferred embodiments, the reagent is selected from, but not limited to, one of the following: glucose oxidase, lactate dehydrogenase, peroxidase, and galactose oxidase.
In some embodiments, the test strip further comprises a multiplicity of electrically conductive testing contacts capable of transferring current between the reaction area and the measuring device. In certain of these embodiments, the testing contacts are located on a first major surface of the test strip, and the indicator contacts are located on a second major surface of the test strip. In other embodiments, the testing contacts and indicator contacts are located on the same major surface of the test strip. In preferred embodiments, the testing contacts comprise a conductive material selected from, but not limited to, carbon, gold, silver, platinum, nickel, palladium, titanium, copper, or lead.